Thursday 19 March 2020

REPAIR / SERVICING TV BBK LD1534SU

Technical description and composition of the BBK LD1534SU TV, type of panel and applicable modules. The composition of the modules.
BBK
Model: LD1534SU
Panel: HT156WX-100
Inverter (backlight): with integrated PSU
PWM Inverter: OB33060P
MOSFET Inverter: ME4940
Trans Inverter: LA09EFD20-612 1022
Power Supply (PSU): LCD037 rev1.0
PWM Power: PWM SOT23-6 (JL1)
MainBoard: L2M30 (02)
IC MainBoard: sound SA7454 18pin optics 1200 120X AM5888S LF MT1389DE
Tuner: DME-7051BL-PLL1
Control: Cone
Technical Specifications LD1534SU
BBK LD1534SU
General recommendations for repairing TV LCD
Possible malfunctions
- BBK LD1534SU does not turn on at all and does not show any signs of operability. Does not blink indicators and does not respond to control buttons.
Most likely in this case, the main switching power supply (IIP) LCD037 is faulty. It is necessary to measure its secondary output voltages, and in case of their absence, check the serviceability of the power switches of the converters and rectifier diodes for a short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during short circuit in the elements of the primary circuit, the mains fuse usually breaks.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. It can be supply, damper circuits, or elements of OOS (negative feedback) stabilization. The reason for the breakdown of the power switch may be PWM (PWM) PWM SOT23-6 (JL1). It is checked only by replacement with a known good one.
- There is no image, there is sound, it is responding to the remote control. Or immediately after turning on for a second, the image may appear and immediately disappear.
The defect can be caused by problems in the nodes or elements of the backlight of the display, or in the power supply of the lamps or inverter. If all the electrolytic capacitors of the filter according to the power supply of the inverter are working, make sure that the lamps are working, then you need to check the converter keys and the secondary windings of the transformers.
If in diagnosing a malfunction, it is necessary to disable the inverter protection, there is a risk of failure of the power elements of the inverter, and special care is required during work, and after they are finished, it is necessary to restore the protection circuits for further safe operation of the TV by the owner in normal mode.
- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the L2M30 (02) motherboard should begin by checking the stabilizers and power converters needed to power the microcircuits and matrix. If necessary, update or replace the software (software). Sophisticated MB board repair (SSB) is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace the elements with sound SA7454 18pin optics 1200 120X AM5888S LF MT1389DE. BGA chip malfunctions are usually easy to detect by warming up.
If there is no reception of television channels, but the TV is working properly from external devices, first of all, check the voltage of the tuner DME-7051BL-PLL1 and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
Attention! Users and owners of LD1534SU TVs who do not have the appropriate qualifications, knowledge and experience are strongly advised against self-repair attempts in order to avoid negative consequences that could lead to complete non-repairability of the device.


SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    BBK LD1534SU


 Service Manual with Schematic Diagram 40 pages 2010  model LD1534SU

 The appearance of the MainBoard L2M30 is shown in the figure below:
L2M30
The appearance of the power supply
Main features of the BBK LD1534SU device:
Installed matrix (LCD panel) HT156WX-100.
To power the backlight, a converter is used, combined with a power supply, controlled by the OB33060P PWM controller. A transformer LA09EFD20-612 1022 is installed in the inverter converter. Keys of type ME4940 are used as power elements of the inverter.
The necessary supply voltages for all nodes of the BBK LD1534SU TV are generated by the LCD037 power supply module or its analogs using PWM SOT23-6 (JL1) microcircuits.
MainBoard - the main board (motherboard) is an L2M30 module, using sound chips SA7454 18pin optics 1200 120X AM5888S LF MT1389DE and others.
The tuner DME-7051BL-PLL1 provides the reception of television programs and tuning to channels.
 Brand: BBK, Model: LD1534SU.
Shortly from the TV: LCD, 720p HD, diagonal 15 "(40 cm), there is HDMI, there is USB.
The composition uses MainBoard L2M30 (02) and an LCD panel (matrix) HT156WX-100.
Power Supply Unit (PSU) LCD037 rev1.0 Power Supply.
BBK LD1534SU LCD TV with HT156WX-100 LCD, 15 "(40 cm) diagonal size 16: 9 format. 250 cd / m² screen brightness is provided by CCFL (EEFL) fluorescent lamps. Maximum brightness to minimum ratio (contrast) ) is 500: 1. You can view images in high quality HD at a resolution of 1366x768 pixels in the standard for graphic decomposition 720p (HD Ready). The input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in stand . Max 480i, 480p, 576i, 576p, 720p, 1080i Supported multimedia file formats:. MP3, WMA, MPEG4, VideoCD, SVCD, Picture CD, JPEG Stereo realized by two built-in speakers using audio NICAM STEREO processing system..
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x2, SCART, RGB, VGA, HDMI, USB. An output for connecting headphones is provided. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector is used on the TV case, this interface supports resolutions: 640x480, 800x600, 1024x768.
The power consumed by the TV in the operating mode from the network is 40 watts.
Overall dimensions: 400x287x185 mm.
TV Weight: 4 kg.
Attention! The BB15 LD1534SU LCD TV panel HT156WX-100 is its most expensive component.
Avoid hitting the glass and exerting pressure on the screen to avoid permanent damage to the LCD panel!